Winch and improved sheave

A winch comprising:

• a sheave for advancing a rope looped around said sheave by application to said sheave of rotational forces comprising:
• a central hub and opposed, facing first and second surfaces radially outwardly extending from said hub to an outer perimeter,
• each of said opposed surfaces being provided with alternating primary ridges and valleys extending from said hub to said outer perimeter, the primary ridges of said first one of said surfaces being aligned with a valley of the opposed second surface,
• said valleys being tapered in width toward said hub of said sheave and having a generally flat floor surface, the center of each said valley having a secondary ridge projecting from said floor surface, said secondary ridges each being of a height extending above its associated valley floor surface that is substantially less than the height of said primary ridges, each of said secondary ridges being in at least approximate alignment with a primary ridge of said facing sheave surface;
• means for rotatably mounting said sheave;
• and
• a hand crank interconnected with the hub of said sheave for application of rotational forces thereto.

A winch comprising

• a rotatable sheave mounted for rotation, and means for application of rotational forces thereto,
• said sheave having a base and two opposed faces with a plurality of generally radially extending alternating primary ridges and valleys circumscribing each of said two opposed faces of said sheave, each of said primary ridges extending outwardly from the base of said sheave in a curvilinear direction curving toward a rotational direction in which said rope is advanced, said primary ridges being positioned at regular intervals around the circumference of said sheave, said primary ridges projecting a first height above the surface of said valleys,
• a generally radially extending secondary ridge projecting from the center of the surface of each of said valleys, each of said secondary ridges having a second height, said second height being a minor fraction of said first height,
• a guiding cam surface adjacent to the outer perimeter of said sheave which maintains the rope in contact with said sheave,
• a housing within which said sheave is rotatably mounted, said housing being open for insertion and removal of a rope or cord around said sheave, and,
• a releasable ratchet mechanism which, when engaged, permits rotation of said sheave only in said rotational direction, and which, when released, permits free rotation of said sheave.

A winch comprising

• a rotatable sheave mounted for rotation,
• means for application of rotational forces to said sheave,
• a handle operatively connected to said sheave for causing rotation thereof,
• said sheave having a base and two opposed faces with a plurality of generally radially extending alternating ridges and valleys circumscribing each of said two opposed faces of said sheave, said ridges being positioned at regular intervals around the circumference of said sheave, said ridges projecting a first height above the surface of said valleys,
• a movable guiding cam surface movable between a use position adjacent to the outer perimeter of said sheave which maintains the rope in contact with said sheave and a release position spaced from said sheave wherein a rope can be placed on or removed from said sheave,
• a releasable lock for selectively maintaining the guiding cam surface at the use position and the release position,
• a housing within which said sheave is rotatably mounted, and,
• a releasable ratchet mechanism which, when engaged, permits rotation of said sheave only in said rotational direction, and which, when released, permits free rotation of said sheave.